NASA: Discovery to launch on Tuesday

NASA will try to launch Discovery on the first space shuttle mission in more than two years next Tuesday, and may press ahead with liftoff even if there's a repeat of the fuel gauge problem that halted last week's countdown, spokesman Bruce Buckingham said in a televised press briefing late Wednesday.

Mission managers decided Wednesday night to bypass another fueling test of Discovery and go straight for the real thing in an effort to understand and either fix or work around the fuel gauge failure, says the AP. The most probable cause is an electrical grounding problem lurking inside the spacecraft.

"We believe the best way to go through this is to do a countdown," said shuttle program manager Bill Parsons. "If the sensors (gauges) work exactly like we think they will, then we'll launch on that day. If anything goes not per the plan that we've laid out in front of us, then we'll have a scrub and we'll have to talk about it."

Multiple safety nets are in place "to ensure we don't proceed unless we feel we're safe to go fly," he added.

But in what would be an almost certainly controversial move in the wake of the 2003 Columbia tragedy, NASA might also proceed with the liftoff if the fuel gauge problem recurs but is considered well understood. That would mean revoking a launch rule requiring all four hydrogen fuel gauges at the bottom of Discovery's external tank to be working properly, and instead relying on just three out of four, says the AP.

The current launch window ends July 31, after which the mission might have to be postponed until Sept. 9 to obtain maximum lighting conditions so Discovery's ascent can be photographed by a new network of cameras.